Method of and apparatus for inspecting strip material



1944- c. J. KLEIN ETAL ,3

METHOD OF AND APPARATUS FOR INSPECTING STRIP MATERIAL Filed Aug. 24, 1938 4 Shets-Sheet 1 fig.l;

INVENTOR Clarence J. file/in .Ern est W. Rzfeger Allan W. Dunccuz Feb. '22, 1944. '.,.J. KLEIN ETAL 2,342,474

METHOD OF AND APPARATUS FOR INSPECTING STRIP MATERIAL F il ed Aug. 24, 1938 Sheets-Sheet III xmmm

INVENTORS Clarence J. .Hlez'n 752 at W fiieger All W Duncan mam m,2 V4a/M c. J. KL EIN ETAL 2,342,474

METHOD OF AND APPARATUS FOR INSPECTING STRIP MATERIAL Filed Aug 24, 1938 4 Sheets-Sheet; a

Feb. 22, 1944.

' I 7 Allan W Duncan Patented Feb. 22, 1944 METHOD OF AND APPARATUS FOR INSPECTING STRIP MATERIAL l Clarence J. Klein, Hollidays Cove, W. Va., and Ernest W. Rieger, Bloomingdale, and Allan W. Duncan, Steubenville Ohio, assignors to Bethlehem Steel Company,

sylvania a corporation of Penn- Application August 24, 1938, Serial No. 226,50

, 7 Claims.

Our invention relates in general to a method of and apparatus for inspecting strip material, andit is particularly applicable for inspecting metal in strip form for holes which may appear therein,

but it may also be used for inspecting other material' in strip form. Inasmuch as it is of great value in inspecting strip metal, it will be described with reference thereto, it being understood, however, that this is not the only appli-. cation of our invention.

In forming material, for example strip metal to be used for tin plate, it is the common practice to roll the metal in long strips on a hot mill of the four-high type to a thickness usually above .05". The hot rolled strip is then pickled, washed and cleaned, and is then cold rolled on a four-high mill to the desired thickness and wound into coils or reels as it leaves the mill. This cold rolled material is passed from the reels through a cleaning and cutting line where the side edges are trimmed to the desired width and the sheets cut to length and stacked. Subsequently the stacked sheets are annealed and after cleaning,

the annealed sheets may be sold a black sheets detected, and are later used in the fabrication of fluid tight containers, the container will have to be discarded, if .the holes are'then found, be-

cause a very minute hole will' cause deterioration and spoilage of the contents. If the. hole is not ,found the contents of the container will more or less be affected by air and content leakage, and lOss will 'result. It is apparent that a first class merchantable sheet to be used for fluid containers should be free from holes.

To insure that. all holes in the sheet are de tected, we have developed a photo-electric eye apparatus and method for using the same. This apparatus and method can be employed at any desired place in the sheet manufacturing process mark made on the strip so as to indicate the length of'the strip wherein the hole appears. This is done while the strip is passing through the apparatus at a high rate of speed usually in excess of 600 feet per minute or more. The

mark placed on the material is readily discernible to the inspector and the sheet on whichit appears is discarded or used for purposes where holes therein are not disadvantageous.

In the drawings there is shown apparatus suitable for carrying out our invention interposed in a cleaning and cutting up strip line. The apparatus consists in eneral of a photo-electric scanning device and marking apparatus, the operation of which is controlled by the scanning device. The strip to be inspectedis passed between guides which take care of irregular edged strip and prevent leakage of. light to the cell. After passing through the guides the portions protected by the guides are cut off by regular edgetrimmers associated with the apparatus. 'The marker may be positioned between the cell and the edge shears or beyond the edge shears, depending on the operating characteristics of the cell and the marker.

By means of our invention the detection of holes in the strip material of suilicient size to permit a beam of light to pass therethrough is positive and accurate. The apparatus is quite inexpensive, has low operating and low maintenance costs and can bereadily, positioned at practically any desired place in the processing of the'strip material. In the drawingsin which we have shown for illustration only the present preferred embodiment of our invention;

Figure 1 represents a top plan view of suitable apparatus,

Figure 2 .is a view inelevation, partly in section, along the line 11-112 of Figure l, Figure 3 is. a view in section along the line Ill-m of Figure 2,

Figure 4 is a view in elevation from the right of and looking toward Figure 1,

Figure 5 is a diagram of the electric control circuit,

Figure 5 is a detail in elevation of a suitable marking device, and

Figure 7 is a detail in section along the line VII-Nil of Figure 2.

In the drawings there is shown a photo-elec tric scanning device P, edge shears S, and a marking device M.

The scanning device P consists of a photoelectric cell holder 2 which is supported on a concrete base 3 by bolts 4. The studs have thereon an interiorly threaded sleeve 5 and a nut t. The cell holder 2 may be adjusted vertically by manipulating the sleeve 5 and the nut 6. Inside the cell holder 2 a photo-electric cell 1 is mounted.

The strip 8 is guided to and through the scanning apparatus by lower entry guides 9, upper entry guides 10 and edge guides H. The lower guide 9 is made up of blocks which are assembled in spaced apart parallel relationship and each is fastened to a transverse support I? which in turn is secured to the framework l3. The top of the lower guide 9 is at the pass line of the strip 8. The top of the cell holder 2 and the top of the photo-electric cell i are just below the pass line. The upper guide it! is made up of blocks which are assembled in spaced apart parallel relationship fastened to an angle IS. The angle I5 is adjustably supported on screw shaits threaded through nuts secured to a transverse supporting member l6 which is connected to the framework i3. By means of hand wheels on the screw shafts M, the guide it may be adjusted to a desired position immediately above the guide 9 moved away from the lower guide 9 when it is desired to thread the strip through the apparatus. The blocks comprising guides 9 and I9 are made of soft metal or of wood so as not to marl: the strip, and the blocks are separately removable so that various widths of strip may be accommodated.

Strip material as rolled has irregular edge portions which are trimmed off at some point in the processing of the strip, and we have taken advantage of this fact to prevent light from passing between the edge guides H and the edges of the strip 3. Such light would affect the photoelectric cell 1 even though the strip were tree from holes. The edge guide H, see particularly Figure 7, is made up of an edge portion H which has grooves l8 therein. These grooves are deep enough to take care of the irregularity of the edge of the sheet. The edge piece 11 is secured to a cross bar l9 by means of a plate 2s. A pin 2| passes through the plate and through the edge piece l1 and holds the edge piece in position. The grooves I8 are so arranged that either of the four grooves shown can readily be presented to the edge of the strip by proper reversal of the portion l'l. This arrangement prolongs the life of the edge portions. The cross bar I9 is secured to supporting member l2 and to supporting member 22 by bolts which are received in slots in the supporting member 12 and a similar member 22. This allows the edge guides H to be-adjusted so as to take care of various widths of sheets. The edge portions l! of the guides ll may be conveniently made of brass or metal, which will not injure the strip or wear too rapidly, and they are spaced apart so that the minimum distance between them is the same as the width of the huished sheet after the edges have been trimmed.

A cover plate 23 with a turned up edge is fas ascents issued to the cross bar it and closely fitted against the top oi the photoelectric cell holder 2. The plate 23 has angle members 24 fastened along its sides and ends. A light proof canvas curtain 25 is attached to the angles 24 and extends toward the center line of the photo-electric cell holderi and interiorly oi both the guides H as shown in Figure '3. The top of the canvas curtain it extends up to the pass line.

At the right hand side of the cell holder 2 as viewed in Figure 2, there is arranged an exit supporting bed 26 which is made up of individual blocks of metal or wood, arranged parallel to one another and to the center line of the strip 8. The ends of the bed or guide 26 are supported on the cross bar 22 and on a cross bar 21. The here 22 and 2'! are in turn secured to the housing 28 of the edge shear S. A number of upper guide pieces 29 are secured to a cross bar 30 which her is in turn secured to the supporting member 22. These pieces are formed of a material which will not mark the strip and they extend downwardly toward the strip 3 and then parallel to it to a position a. little beyond the center line oi the edge shear S. The bed 26 and the upper guide pieces 29 are made in separate removable sections so that by removing or inserting sections various widths of sheets may be accommodated.

Two light reflectors 3i and 32 are secured to a cross bar 33 which in turn is secured to adjustable uprights 34. The light reflectors are positioned so that the rays of light from the lamps contained therein will be projected directly on the top of the photo-electric cell 1, or on the top of the strip 8 directly thereabove.

The edge shears S include a pair of cutting discs 35 secured on a shaft 36. The cutting discs 35 are arranged in shearing relationship to similar cutting discs 31 which are keyed to a shaft 39 which is positioned directly below the shaft 35. These cutters are of a well-known type and are adjustable to accommodate various widths of sheets. The ends of the shafts 36 and 38 are iournalled in the housings 28, which housings are in turn secured to the framework of the scanning device P.

The marking device M shown in Figures 2, 4 and 5, consists of a solenoid 39 mounted in a desired position on a support 40 which in turn is secured to the housings 28 of the shear S. The core B! of the solenoid is pivotally secured at one end to a lever 42 which is pivoted at 43. The other end of the lever has attached to 'it a marker 44 which is here shown as a piece of crayon. If desired, instead of a crayon a cutting or scratching tool could be used. In fact, we

prefer to use a cutting tool since a crayon may injuriously mark the sheet immediately thereabove during the annealing process, if the sheets are subsequently annealed. Upon energization of the solenoid 39 the crayon 44 (or marking tool) will be forced down on the strip 8 and will mark it. A support 45 is provided for the strip in the vicinity of the marking tool. When the solenoid 39 is energized by an electric current controlled by the photo-electric cell 1, the lever 42 is operated to cause the marker 44 to contact and mark the strip 8.

Instead of using a solenoid to actuate the marking device M, an arrangement using an electro-magnet can be employed. It is, of course, understood that the marking device whether the solenoid or of the electro-magnetic type or of any other type, can be located at any part of the width of the strip. We have shown the solenoid 39 as being located at the center of the strip, whereas the markingdevice of the electromagnetic type is placed near one edge of the sheet. A suitable marker device M of the electro-magnetic type is illustrated in Figures 4 (right hand) and 6. The device consists of an electro magnet 45 secured to supports 41 which in turn are adjustably connected by means of the framework 40 to the housings 28 of the edge shear S. An armature 49 is pivoted at to the supporting framework 40. The armature has depending lugs 5| which contact the side of the magnet housing to limit the upstroke of the armature and a handle 52 whereby the armature can be moved manually. One end of the armature 49 tests on a nut 53 which is attached to a pusher bar 54. Around the pusher bar 54 and between the nut 53 and the support 41, a coil spring 55 is placed; and between the armature 49 and'a nut 56 at the top of the pusher bar 54, a coil spring 51 is placed. To the lower end of the pusher bar 54, a marking tool such as a cutting tool 58 is secured. When the magnet 46 is energized the cutting tool 58 marks the strip 8 which is passing thereunder. Such a mark. is indicated as 580.

It is apparent that the marking device, whether of the solenoid type' first described or of the electro magnet type last described, can be placed before or behind the edge shears S or at any other convenient place in the line. Both the marking devices are here shown as behind the edge shears S. The positioning of the markers depends on the operating characteristics of the marking device and the speed. of travel of the placed on the strip at a position in the transverse plane of the hole which has caused the scanning device to operate.

The electrical hook-up of the photo-electric cell P and the marking device M is shown in Figure 5. The photo-electric cell 1 is connected to the magnetic coil C. A change in the electricout put of the photo-electric cell 1, caused by an impingement thereon of a ray of light from the source of illumination (lights 3| and 32), is suf- .ficient to energize the coil C and attract the armature A which closes an electric circuit through the coil ofthe marking device M. This will cause the crayon (or marking tool) to be forced against the sheet. When the light ray to the cell I is shut ofi, the coilC is deenergized suillciently to release the armature A and thus cut off the current to the marking device M whereon the crayon (or marking tool) is lifted from the sheet.

The apparatus has been described as applied to a cleaning and cutting'up line. In such an arrangement, a strip of material is fed through the apparatus from left to right (see Figures 1 and 2) bythe action of rolls not here shown, and which form no part of our invention. It is apparent that the apparatus could be placed in some other location through which the strip is passed.

While-the strip is passing through the scanning device P is free from holes, no ray of light can pass from the light reflectors 3| and 32 to the photo-electric cell 1. If the strip 3 has a hole or holes therein between the edges of the guides ll, light will pass therethrough and affect the photoelectric cell I. The marking device which is electrically connected to the cell '1, will then be operated to mark the strip. As all electro magnets with which we are familiar have a time lag, itis necessary that the marking device M be placed at a distance from the cell along the line of passage of the strip, so that the mark when made on the strip will be in the same transverse plane as the hole. The unscanned edges of the sheet protected by the opaque guides are trimmed off. Themarked sheet when out and annealed can be readily detected by an inspector and discarded.

' While we have illustrated and described certain preferred embodiments of our invention, it will be understood that the invention is not limited thereto, and that various changes in the shape, size, number and arrangement of parts may be resorted to withoutdeparting from the spirit of our invention or the scope of the following claims.

We claim:

1. The method of continuously handling strip material which comprises moving the material between a light source and a photo-electric cell coextensive with the width of the material which it is desired to inspect with the edge portions of the strip in overlapping relation to opaque guides whereby the cell may be energized only by light projecting through a perforation in the portion of the strip located between the guides, and thereafter trimming the edges which overlapped the opaque guides while the strip is still in alignment with the guides.

2. Apparatus of the class described'comprising in combination, means for projecting light against one face of the strip material to be trimmed across the full width of the strip, opaque guides at the point of illumination of the material overlapping the edges of the material, means adjacent the 0pposite face of the strip responsive to any light which may pass through the material, means located beyond the light-projecting means and in alignment with the guides for shearing the screened edges of the strip while the strip is moving and signalling means operated by the light responsive means for indicating the presence of a defect in the strip between the guides.

3. Apparatus of the class described in which strip material is inspected as it moves through the apparatus comprising in combination means for shearing the edges of the strip, means in advance of the edge shear for projecting light against one face of the strip material to be trimmed across its full width, means adjacent the opposite face of the strip responsive to any light which may pass through a perforation in the material, light screens at the point of illumination of the material interposed between the light source and the light responsive means for overlapping and screening the edges to be sheared, said edge shearing means being disposed beyond the projecting means and arranged so as to cut oil? the screened edge portions of the strip, and means succeeding the shear operated by the light responsive means and so positioned as to mark the unscreened material in the vicinity of the perforation after it has passed through the edge shear.

4. Apparatus of the class described in which strip material is inspected as it is being. moved from one point to another, comprising photo-electric scanning means for detecting holes in the material in only that portion which extends from the center toward the edges a distance less than the full width of the strip as it moves between said points, means the operation of which is initiated by the operation of the scanning means 75 for marking the strip in the vicinity in which holes occur and means succeeding the sconnlng means and in alignment with the steamed ocrticrrs of the strip for edge trimming the uhscermecl edge cor tions of the strip.

5. Apparatus oi the class descrlhecl m which strip material is inspected while beingmoved from one point to another, comorlslng a, source of illumination located between said points; a photoelectric cell located at the some point but on the opposite side of the strigo to the source of the illumination, and means in which the edges of the strip are received for screemne the edges of the strip interposed between the source oi ll luminstion and. the photo-electric cell, said means commising edge guides extending parallel to the center line ol the strip and having grooves em tending into the guides in which the edges of the strip are receives.

6. Apparatus of the class describes in which strip material of irregulcr width is inspected while being moved from one point to another, scanning: means including a source of illumination locetecl between said points and c photoelectric cell lo cated at the some point but on the side of the strip opposite to the source of the illumination, means for overlspmng and screening the edges of the strip interposed between the source of il-= luminat-ion and the photoelectric cell, said means comprising edge guides extending parallel to the center line of the strip ami having grooves extending into the guides in which the edges of the messes strip ore received so adjustable sheer positioned closely adjacent and beyond the scanning means v for cutting ofi the mcarmeol edges of the string lit an, erllustcble bed composed of strips of material soitertlien the strip material to be inspected over which the strip is moved as it passes from the scanning means, and, adjustable guide means spaced above the bed and above the path of the strip and extending from a position adjacent the photoelectric cell to the point of engagement of the strip and shear.

7. Apparatus of the class described in which strip material having portions of irregular width is inspected whil the material is being moved from one point to another, comprising photo-electrio scanning means for detecting holes in a desired cross section of the material extending from the center line of the strip outwardly to s polct short of the edges of the strip as it moves between saicl points, means overlapping and screening the edges of the strip as they pass the scanning mes-us, means controlled by the scanning means for marking the cross section of the strip in which holes occur and means adjacent and beyond the screening means and in alignment therewith for shearing the screened edges of the strip. 

